(Not Applicable)
(Not Applicable)
The present invention relates generally to automotive mounting devices, and more particularly to a motor mount insert for retrofit application to an automotive motor mount.
As is well known in the automotive industry, automotive engines or motors are normally installed in trucks and automobiles by mounting them to a cross-member of the vehicle frame via a pair of motor mounts. One particular type of prior art motor mount referred to as a xe2x80x9cclam shellxe2x80x9d type motor mount comprises a metal backing plate and a metal shell which have a rubber core or insert disposed therebetween. The shell is typically spot-welded to the backing plate, with the rubber core having a configuration which is complimentary to that of the shell so as to be maintained between the shell and the backing plate. The attachment of the motor mount to the cross-member is accomplished by positioning the backing plate upon the top surface of the cross-member. Thereafter, a series of mounting bolts are advanced through respective coaxially aligned sets of apertures disposed within the shell, backing plate and cross-member, with nuts then being applied to the exposed ends of the mounting bolts protruding from the side of the cross-member opposite that having the backing plate of the motor mount positioned thereupon. The rubber core of the prior art motor mount is not formed from rubber alone, but rather comprises a metal base plate having rubber molded thereabout. The base plate itself defines an elongate, circularly configured bore which extends therethrough, and two pairs of tabs which are disposed at respective ones of the opposed ends thereof.
The prior art motor mount is specifically configured to cooperatively engage a corresponding engine bracket of the engine or motor. More particularly, the motor mount is configured such that the engine bracket may be advanced thereover in a manner wherein a pair of apertures disposed within the engine bracket are placeable into coaxial alignment with the bore of the base plate of the rubber core. Once such coaxial alignment has been achieved, a long bolt is advanced through the coaxially aligned apertures and bore, thus facilitating the attachment of the engine bracket to the motor mount. The base plate of the rubber core is formed such that the tabs defined thereby engage the engine bracket in a manner which facilitates the coaxial alignment of the apertures of the engine bracket with the bore of the base plate. More particularly, the engine bracket, when advanced over the shell of the motor mount, engages the pair of tabs at each end of the base plate, with such engagement resulting in the apertures of the engine bracket and bore of the base plate being placed into coaxial alignment with each other, thus allowing for the passage of the long bolt therethrough to facilitate the attachment of the engine bracket to the motor mount.
The prior art motor mounts, when used to facilitate the attachment of the engine or motor to the cross-member of the vehicle frame, effectively dampen excess vibration of the engine due the resiliency of the rubber cores thereof. In this respect, movement of the engine or motor and hence the engine brackets is translated into movement of the shells of the motor mounts, with such movement being dampened by the rubber cores thereof.
Although the prior art motor mounts have proven generally suitable for their intended purposes, they possess certain deficiencies which detract from their overall utility. More particularly, as indicated above, the prior art automotive motor mounts of the clam shell type utilize rubber as the resilient material to fabricate the cores thereof. As is well known to those skilled in the art, rubber is susceptible to degradation due to various environmental factors, such as contamination by automotive fluids, e.g., gasoline, oil, transmission fluid, brake fluid, etc., as well as ozone and other atmospheric pollutants. Thus, over time, the rubber cores of the prior art motor mounts typically wear and shrink (as well as being susceptible to other forms of degradation) which substantially reduce or completely impede their efficacy in dampening vibrations and other movements of the motor. As will be recognized, the failure of one or both of the rubber cores of the motor mounts typically results in excess vibration or movement of the motor during operation of the vehicle as could result in damage thereto. Further, the rubber material for the prior art motor mount cores is incapable of applying a substantial pre-load to the shells so as to both desirably increase the stiffness of the motor mount and similarly increase the durability thereof.
With clam shell type motor mounts as currently know in the prior art, once one or both of the rubber cores of the motor mounts become worn, typically the entire motor mount is removed and replaced. As can be appreciated, replacing the entire motor mount as opposed to only the rubber core thereof gives rise to significantly increased costs in the repair operation. Thus, there exists a need in the art for a motor mount insert which can be easily and quickly retrofitted to the shell and backing plate of an existing clam shell type motor mount, thus eliminating the need to replace the entirety of the motor mount.
The present invention overcomes the deficiencies of prior art motor mounts by providing a polyurethane motor mount insert which may be retrofitted to the backing plate and shell of a prior art clam shell type motor mount. More particularly, the motor mount insert of the present invention may be used as a replacement for the rubber core of the prior art motor mount, and operatively positioned between the existing backing plate and shell. The motor mount insert of the present invention itself includes an internal metal base plate which is specifically adapted to allow for the formation of inserts retrofittable to different models of clam shell type motor mounts. The polyurethane construction of the present motor mount insert overcomes the above-described deficiencies associated with the use of rubber, and provides increased durability and reduced susceptibility to failure. These, and other advantages attendant to the present invention, will be discussed in more detail below.
In accordance with the present invention, there is provided a motor mount insert for retrofit application to a motor mount which is attachable to a engine bracket having a pair of apertures disposed therein. The motor mount is of a clam shell type and includes a backing plate and a shell which, when attached to each other, collectively define a cavity having a maximum cavity width and maximum cavity height. The motor mount insert is positionable between the shell and the backing plate upon the removal of the existing prior art rubber core, and secured therebetween when the shell and the backing plate are reattached to each other.
The motor mount insert of the present invention comprises a base plate which defines a first end having a first pair of tab portions extending therefrom in spaced relation to each other, and a second end having a second pair of tab portions extending therefrom in spaced relation to each other. The base plate further defines an elongate bore which extends therethrough. In the preferred embodiment, the base plate itself comprises a generally rectangular first plate section having a first channel formed therein and first and second flange portions extending therefrom in spaced relation to each other. More particularly, the first plate section includes a body portion, with the first and second flange portions extending along and from respective ones of the opposed longitudinal sides of the body portion in opposite directions. The first and second flange portions preferably extend angularly relative to the body portion, and each have opposed ends which define respective ones of the tab portions of the first and second pairs. The tab portions of the first and second pairs defined by respective ones of the opposed ends of the first flange portion preferably exceed the size of the tab portions of the first and second pairs defined by respective ones of the opposed ends of the second flange portion. Additionally, the first channel formed in the body portion of the first plate section is not of a uniform size, but rather defines a spaced pair of enlarged regions.
In addition to the first plate section, the base plate comprises a generally rectangular second plate section which is rigidly attached (e.g., spot-welded) to the first plate section. The second plate section itself includes a second channel formed therein which is identically configured to the first channel, and thus defines a spaced pair of enlarged regions. When the first and second plate sections are attached to each other to define the base plate, the enlarged regions of the first channel are generally aligned with respective ones of the enlarged regions of the second channel, with the first and second channels collectively defining the bore which extends longitudinally through the base plate. The first and second plate sections are each preferably fabricated from a metal material, such as stainless steel.
In addition to the base plate, the motor mount insert of the present invention comprises a resilient material which is molded about the base plate in a manner wherein the first and second pairs of tab portions protrude from respective ends thereof. The resilient material is formed to have a maximum material width which is preferably substantially equal to the maximum cavity width of the cavity. The resilient material is also formed to have a maximum material height which preferably exceeds the maximum cavity height of the cavity such that a pre-load is applied to the motor mount insert upon the attachment of the shell to the backing plate subsequent to the motor mount insert being operatively positioned therebetween. The resilient material is preferably formed to include identically configured first and second block sections which are separated by a trough. The first and second block sections are preferably formed to have configurations which are complimentary to those of an identically configured pair of recesses formed in the shell of the motor mount in spaced relation to each other. As such, upon the attachment of the shell to the backing plate subsequent to the motor mount insert being operatively positioned therebetween, the first and second block sections of the resilient material are received into respective ones of the recesses of the shell in a nesting fashion, with such receipt maintaining the motor mount insert in its operative position between the shell and the backing plate. A preferred resilient material for the motor mount insert is polyurethane.
In one embodiment of the present motor mount insert, the resilient material is molded about the base plate such that the first flange portion of the first plate section defining the larger tab portions of the first and second pairs extends away from the first and second block sections of the resilient material (i.e., the second flange portion of the first plate section defining the smaller tab portions of the first and second pairs extends toward the first and second block sections). In an alternative embodiment of the present motor mount insert, the resilient material is molded about the base plate such that the second flange portion of the first plate section defining the smaller tab portions of the first and second pairs extends away from the first and second block sections of the resilient material (i.e., the first flange portion of the first plate section defining the larger tab portions of the first and second pairs extends toward the first and second block sections). Advantageously, by altering the orientation of the base plate within the resilient material in the aforementioned manner, motor mount inserts may be fabricated for use in the two most commonly employed clam shell type motor mounts without the need to modify the structure or configuration of the base plate. The enlarged regions of the first and second channels of the first and second plate sections which collectively define the bore effectively reduce the amount of resilient material needed to be molded to the base plate, thus lowering the fabrication cost of the present motor mount insert.
Further in accordance with the present invention, there is provided a method of fabricating a motor mount insert for retrofit application to a motor mount attachable to an engine bracket having a pair of apertures disposed therein, and including a backing plate and shell which, when attached to each other, collectively define a cavity having a maximum cavity width and a maximum cavity height. The method comprises the initial step of providing a base plate which is formed to define a first end having a first pair of tab portions extending therefrom in spaced relation to each other and a second end having a second pair of tab portions extending therefrom in spaced relation to each other. Thereafter, a resilient material is molded about the base plate such that the first and second pairs of tab portions protrude therefrom and the remainder of the base plate in encapsulated by the resilient material.
In the motor mount insert fabrication method of the present invention, the base plate is preferably formed to include first and second flange portions which extend in spaced, generally parallel relation to each other and each have opposed ends which define respective ones of the tab portions of the first and second pairs, with the tab portions defined by the opposed ends of the first flange portion exceeding the size of the tab portions defined by the opposed ends of the second tab portion. Additionally, the resilient material is preferably formed to include a pair of block sections which extend from a common side thereof, and is molded about the base plate such that the first flange portion defining the larger tab portions extends toward the block sections. Alternatively, the resilient material may be molded about to the base plate such that the second flange portion defining the smaller tab portions extends toward the block sections. The resilient material is preferably formed from polyurethane, and to have a maximum material width which is substantially equal to the maximum cavity width of the cavity and a maximum material height which exceeds the maximum cavity height of the cavity.
Still further in accordance with the present invention, there is provided a method of retrofitting a motor mount attached to an engine bracket and a frame of a vehicle, and including a backing plate, a shell attached to the backing plate, and a rubber core positioned between the backing plate and the shell, with a polyurethane motor mount insert. The retrofit method comprises the initial step of detaching the engine bracket from the motor mount, which is followed by the step of detaching the motor mount from the frame. Thereafter, the shell is separated from the backing plate, with the rubber core then being replaced with the motor mount insert. The shell is then reattached to the backing plate with the motor mount insert being positioned therebetween, with the motor mount retrofitted to include the motor mount insert thereafter being reattached to the frame. Finally, the engine bracket is reattached to the retrofitted motor mount. The motor mount insert preferably includes first and second pairs of tab portions protruding therefrom, with one of the tab portions of each of the first and second pairs exceeding the size of the remaining tab portion of the same pair. In this respect, the step of replacing the rubber core with the motor mount insert preferably comprises positioning the motor mount insert between the backing plate and the shell such that, when the retrofitted motor mount is reattached to the frame, the larger tab portion of each of the first and second pairs will have a prescribed orientation relative thereto.